Pressure sensing devices have become ubiquitous the past few years as they have found their way into many types of products. Utilized in automotive, industrial, consumer, and medical products, the demand for pressure sensing devices has skyrocketed and shows no signs of abating.
Pressure sensing devices may include pressure sensors as well as other components. Pressure sensors may typically include a diaphragm or membrane. When a pressure sensor in a pressure sensing device experiences a pressure, the membrane responds by changing shape. This change in shape causes one or more characteristics of electronic components on the membrane to change. These changing characteristics can be measured, and from these measurements, the pressure can be determined.
Often, the electronic components are resistors that are configured as a Wheatstone bridge located on the membrane. As the membrane distorts under pressure, the resistance of the resistors also changes. This change results in an output of the Wheatstone bridge. This change can be measured through wires or leads attached to the resistors.
These pressure sensors may be manufactured as die on one or more silicon wafers. These one or more silicon wafers may be fairly costly to procure and to handle. Further, these one or more silicon wafers may undergo multiple processing steps, each requiring the use of expensive equipment and chemicals as well as the time of highly qualified individuals. Accordingly, the costs for these processed wafers may be high.
The cost of manufacturing each salable die is proportional to these costs divided by the number of functional die per wafer. Accordingly, to reduce the cost of each functional die, it may be desirable to reduce the size of each die. This may increase the net number of die per wafer. It may also be desirable to manufacture the die using a reliable process in order to increase the percentage of die that are functional. This may increase the number of functional die per wafer.
Thus, what is needed are pressure sensors having a reduced size and that may be reliably manufactured.